Square battery lower box body structure

Abstract

The invention discloses a square battery lower box structure, which comprises a rectangular lower shell formed by sheet metal, a battery module arranged on the lower shell, a flange arranged on the periphery of the lower shell, and a reinforcing frame formed by sheet metal and arranged on the lower side of the lower shell, wherein the reinforcing frame at least comprises reinforcing longitudinal beams and reinforcing transverse beams which are arranged in a crossed mode, each of the reinforcing longitudinal beam and the reinforcing transverse beam comprises a downward convex part so as to makethe cross section be in a downward convex n shape, the reinforcing frame is connected with the lower shell in a spot welding mode, assembling long grooves extending to the front end and the rear endare formed in the positions, corresponding to the reinforcing longitudinal beams, of the lower side of the lower shell, the reinforcing longitudinal beams are located in the assembling long grooves, battery hanging frames extending outwards are arranged at the left end and the right end of each reinforcing transverse beam, and the battery hanging frame is provided with a bolt through hole used forbeing connected with a vehicle body bolt. According to the invention, the weight of the lower box body can be reduced so as to improve the energy density of the power battery pack, the strength and rigidity of the lower box body can be ensured, the processing and manufacturing are convenient, and the manufacturing cost is favorably reduced.

Description

technical field [0001] The invention belongs to the technical field of electric vehicle manufacturing, and in particular relates to a lower box structure of a square battery. Background technique [0002] For electric vehicles, the lithium-ion power battery is a key component. With the advancement of technology, prismatic lithium iron phosphate batteries have been rapidly promoted. The power battery pack usually includes an outer box, a battery module fixed in the outer box, the battery module includes a number of battery cells, and the outer box is fixed on the chassis of the car by bolts. The outer box includes a lower box and an upper box covered on the lower box. The lower box is the main load-bearing part and needs to have sufficient strength and rigidity, while the upper box mainly protects the battery. The function of the module. [0003] In order to improve the performance of the power battery, at present, new energy car companies are focusing on improving the crui...

AI Technical Summary

Problems solved by technology

[0004] However, the lower box body made of aluminum alloy has the following defects: First, the existing aluminum alloy lower box body is usually made by the following two processes. In the first process, the lower box body is made of extruded aluminum alloy The profile is made by bolt fixing and splicing. Due to the limitation of the extrusion molding process, the shape of the aluminum alloy profile in the length direction is uniform. Therefore, the overall shape of the lower box formed after splicing is relatively simple, especially the shape of the splicing formed The lower box is usually a frame structure, therefore, outside dust, etc. can easily enter the interior through the gap of the frame to pollute the battery module, thus affecting the service life of the power battery

Therefore, an additional layer of protection is required

In the second process, the lower box is formed by die-casting with a large die-casting mold. Although it has the advantages of high dimensional accuracy and convenient assembly and use, the manufacturing cost of the large die-casting mold is extremely high, which will significantly increase the manufacturing cost of the power battery pack. , especially, for power battery packs of different varieties and specifications, the lower boxes have different shapes and sizes, and different die-casting molds need to be manufactured at this time

In other words, its versatility is poor

It is understandable that for electric vehicles, the cost of the power battery pack accounts for a major part of the cost of the vehicle. Therefore, the high manufacturing cost and price of the power battery pack will seriously affect the sales and popularity of electric vehicles.

[0005] Although some people try to use thin steel plates to manufacture the outer box through sheet metal technology, but because the weight of the battery module is heavy, and the vehicle will vibrate greatly during driving, when the thickness of the plate is thin, although there are It is beneficial to reduce the weight to increase the energy density of the battery pack, but it will cause the strength and stiffness of the lower box to be difficult to meet the requirements. In particular, the entire lower box is prone to deformation after a certain period of use, and even damage in severe cases, resulting in battery damage. package unavailable

When the thickness of the plate is increased to meet the strength and rigidity requirements of the lower box, on the one hand, it will greatly increase the difficulty of sheet metal stamping, which requires a larger stamping machine for processing, thereby increasing the manufacturing cost. On the other hand , it will cause the weight of the lower box to be too heavy, thereby reducing the energy density of the battery pack

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